C++ Multi-Client TCP Server with QList - c++

Question

Necessary informations:
QList<QTcpSocket*> list;
QTcpServer* server;
QTcpSocket* socket;
In Qt I have built a TCP-Server(QTcpServer)! I have a QList with all my connected clients and I want to read the incomming data for each client personally. So if the QTcpServer gets a new connection, I handel it like this:
void Server::newConnection()
{
qDebug() << "New Connection";
list.append(server->nextPendingConnection());
connect(list.last(),SIGNAL(readyRead()),this,SLOT(readyRead()));
}
How can I get the correct client (out of my QList), which send the SIGNAL readyRead(), in my SLOT readyRead()?
void Server::readyRead(){
//??
}
Any help is welcomed!

Answer 1

Have you tried QObject::sender()? It should return the instance of the QObject which actually sent the signal. Hope that will help.

Answer 2

The solution:
void Server::readyRead(){
QByteArray buffer;
QTcpSocket* readSocket = qobject_cast<QTcpSocket*>(sender());
buffer = readSocket->readAll();
QString mytext = QString::fromStdString(buffer);
qDebug() << mytext;
}

Answer 3

This could be solved by the QSignalMapper. Here is the (not completelly tested) code:
---------------------- main.cpp ------------------
#include "rootwindow.h"
#include <QApplication>
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
RootWindow w;
w.show();
return a.exec();
}
---------------------- rootwindow.h ------------------------
#ifndef ROOTWINDOW_H
#define ROOTWINDOW_H
#include <QMainWindow>
#include <QtDebug>
#include <QLocalServer>
#include <QLocalSocket>
#include <QSignalMapper>
#include <QList>
class RootWindow : public QMainWindow
{
Q_OBJECT
private:
QLocalServer *server;
QLocalSocket *socket;
QList<QLocalSocket*> *list;
QSignalMapper *mapper;
public:
RootWindow(QWidget *parent = 0);
~RootWindow();
private slots:
void slotNewConnection();
void slotReadyRead(int index);
};
#endif // ROOTWINDOW_H
------------------------ rootwindow.cpp -------------------------
#include "rootwindow.h"
RootWindow::RootWindow(QWidget *parent): QMainWindow(parent)
{
server = new QLocalServer;
list = new QList<QLocalSocket*>;
mapper = new QSignalMapper(this);
connect(server, SIGNAL(newConnection()), this, SLOT(slotNewConnection()));
connect(mapper, SIGNAL(mapped(int)), this, SLOT(slotReadyRead(int)));
server->listen("TestServer");
}
RootWindow::~RootWindow()
{
delete list;
}
void RootWindow::slotNewConnection()
{
qWarning() << "newConnection";
list->append(server->nextPendingConnection());
//here you map each client to its number in the list
mapper->setMapping(list->last(), list->length()-1);
//here we say, that when ever a client from the QList sends readyRead() the mapper should be used
//with the property (list->length()-1) defined in the line above
connect(list->last(), SIGNAL(readyRead()), mapper, SLOT(map()));
}
void RootWindow::slotReadyRead(int index)
{
qWarning() << "Client " << index << " has written: " << list->at(index)->readAll();
}
It's basically your code, I've only added the QSignalMapper and some comments at the relevant lines.